JPS6326839B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high-pressure, high-temperature furnace used when performing high-pressure, high-temperature processing such as powder compacting and sintering or diffusion bonding in a high-pressure, high-temperature gas atmosphere. In recent years, with the progress of technological development, techniques for subjecting objects to various treatments in high-pressure, high-temperature gas atmospheres have been researched and are about to be adopted industrially in various fields. Hot Isostatic Compacting Process or
The Hot Isostatic Pressing Process is one such method, and products formed and sintered using this method can: a) achieve high density at lower temperatures than when using traditional sintering methods; As a result, grain coarsening due to excessive crystal growth is prevented, and a dense structure can be obtained. b Densities close to theoretical values can be obtained for all materials, and the structure is uniform. c) It is possible to sufficiently increase the density of spherical powder that is not suitable for molding. d The mechanical and physical properties of the powder are improved. e The microstructure improves performance, for example, in high-speed steel tools. f Unlike ordinary mold-forming presses, large-sized products can be manufactured because they are not limited by press capacity. g. Health hazards can be kept to a minimum even when handling hazardous and unstable materials. h Various composite materials of metals, ceramics, etc. can be manufactured. i By improving material yield and reducing defective products,
Material costs can be reduced. There are many advantages such as. In addition to shaping and sintering powders, sintering is also possible by taking advantage of the fact that placing an object in a high-pressure, high-temperature gas atmosphere can remove internal defects and increase toughness and transverse rupture strength. Consideration is being given to using it to subject tool materials to high-pressure, high-temperature treatment, or when joining turbine blades to the main body, by diffusion bonding the two in a high-pressure, high-temperature gas atmosphere to obtain an extremely strong bond. . However, although it has many advantages, it is not currently being adopted industrially because the biggest drawback of this method, namely extremely low productivity, remains unsolved. . In order to reduce the manufacturing costs of products, shortening cycle times has become an urgent issue, and the British patent no.
A technique shown in No. 1291459 has been proposed. Hereinafter, with reference to FIG. 1, the technology shown in British Patent No. 1291459 will be explained as prior art to this invention. In FIG. 1, a high pressure chamber 1 is a high pressure cylinder 2,
Composed of an upper plug 3 and a lower plug 4, gas introduced into the high pressure chamber 1 through a pressure introduction hole 5 provided in the upper plug 3 is passed through an upper sealing ring 6 and a lower sealing ring 7 to the high pressure chamber 1. 1
kept airtight inside. Inside the high pressure chamber 1, side, upper and lower heat insulating sheaths 10, 11 and 12 surrounding the processing chamber 8 and heating device 9 are disposed, and the side and upper heat insulating sheaths 10, 11 are suspended from the upper plug 3. A heating device 9 is suspended from the upper heat insulating sheath 11 . An electrode 13 for supplying power to the heating device 9 is provided on the upper plug 3 in an electrically insulated and airtight manner, and the heating device 9 and the electrode 13 are connected to the upper heat insulating exterior 1 through a bush 14.
1 by a power supply conductor 15 passing through it. The object to be processed 16 is placed on the lower heat insulating sheath 12 . In the apparatus having the above configuration, the object to be processed 1
After preheating the lower plug 4 in a separately prepared preheating furnace (not shown) outside the high pressure chamber 1,
The high pressure chamber 1 is placed on top through the lower heat insulation exterior 12
The object to be treated 16, the lower heat insulating sheath 12, and the lower plug 4 are integrally inserted into the high pressure chamber 1 from below, and then high pressure gas is introduced from the pressure introduction hole 5.
A high-pressure, high-temperature gas atmosphere is created in the processing chamber 8, and the object to be processed 16 is pressurized and heated to produce a final product. That is, in the apparatus shown in FIG. 1, the workpiece 1 is heated in the preheating furnace before being heated in the high pressure chamber 1
6 is preheated, the heating time in the high pressure chamber 1 is shortened, and thus the cycle time can be shortened. However, even with this device, it is true that
Although it has the advantage of being able to shorten cycle time, it also requires a preheating furnace in addition to normal high-pressure, high-temperature processing equipment, which increases equipment costs. 16 is transported in the atmosphere, which has the drawback that heat loss due to heat radiation becomes extremely large.More fatally, the high-temperature processing object 16 after preheating is transported through the lower heat insulating exterior 12. Place it on the lower plug 4,
When inserted into the high-pressure chamber 1, the lower inner wall surface of the high-pressure cylinder 2 is overheated due to the heat radiation of the object to be treated 16, and furthermore, the lower sealing ring 7 is damaged due to the overheating of the inner wall surface of the high-pressure cylinder 2, which is a very serious drawback. It has. In other words, the pressure range in which this high-pressure, high-temperature treatment equipment is most often used is around 2000Kg/ ^cm2 ;
Overheating the high-pressure cylinder 2, which needs to maintain an extremely high pressure of 2000 kg/cm ² , will significantly shorten its lifespan and pose a risk of destruction. The most expensive part in high-pressure, high-temperature processing equipment is the high-pressure cylinder 2, and a reduction in the lifespan of this high-pressure cylinder 2 leads to an increase in equipment costs and product costs.Furthermore, since high-pressure gas is used as the pressure medium, It is hard to imagine what kind of accident would occur due to the destruction of a high-pressure cylinder under a high pressure of 2000Kg/cm ² . Furthermore, if the lower sealing ring 7 is damaged, it will no longer be possible to seal high-pressure gas, and not only will high pressure not be generated, but there is a risk that it will lead to a similar accident. In Japan, gas of 10 kg/cm ² or more is called high pressure gas, and it is well known that safety in handling is regulated by the High Pressure Gas Control Law.
As stated in Article 1, the purpose of this law is to prevent disasters caused by high-pressure gas and ensure public safety. Therefore, very detailed standards have been established for the structural strength of high-pressure gas equipment, and in particular strict regulations have been put in place in terms of safety to ensure that all possible measures are taken to prevent disasters and accidents. There is. However, in general, the High Pressure Gas Control Law provides a clear standard for 1000 kg/
^cm2 , and beyond this, it is necessary to demonstrate sufficient design and manufacturing technology for the Minister of International Trade and Industry to recognize that the manufacturing equipment is sufficiently safe. Currently, the pressure range in which high-pressure, high-temperature treatment equipment is most commonly used is around 2000Kg/ ^cm2 , but in this case,
The prefecture where the equipment is installed is the regulatory authority;
In addition to applying for permits for equipment, esp.
The pressure resistance and safety of parts exceeding 1000 kg/cm ² must be confirmed by the Ministry of International Trade and Industry. In other words, in this type of equipment where safety is strictly pursued, no matter how much the cycle time can be shortened, there is a risk of overheating of the high pressure cylinder 2 and further damage of the lower sealing ring 7. Employing a device such as that shown in FIG. 1 is extremely problematic. This invention was made in view of the above-mentioned problems, and aims to provide a highly safe high-pressure, high-temperature furnace that can shorten the cycle time and has no adverse effects on the high-pressure cylinder and other parts of the equipment. Its characteristics include a high-pressure chamber formed by a high-pressure cylinder, an upper plug and a lower plug that seal the upper and lower openings of the high-pressure cylinder, respectively, an insulated exterior, and a heating device inside the insulated exterior. In a high-pressure, high-temperature furnace in which a process such as sintering or bonding is performed on a workpiece placed on the lower plug in a high-pressure, high-temperature gas atmosphere, the lower plug, heating device, heat-insulating exterior, and workpiece are placed on the lower plug. The present invention is provided in such a manner that it can be integrally removed from the high-pressure cylinder at any time, and that a processing chamber defined by the heat-insulating exterior and the lower plug is provided so as to be openable and closable. Here, in the above configuration, the phrase "can be taken out integrally at all times" means that when using the furnace of the present invention, it is not possible to take out the furnace in special cases such as failure or repair, but that taking it out in one piece is a normal mode of use in normal processing. That's what I'm saying. In this sense, the furnace of the present invention achieves its function by being able to take out the entire unit at all times. Hereinafter, the present invention will be explained in detail with reference to illustrated embodiments. FIG. 2 shows an embodiment of the high-pressure, high-temperature furnace according to the present invention, and the present invention will be explained with reference to FIG. In FIG. 2, the high pressure chamber 21 is the high pressure cylinder 2.
2. Consisting of an upper plug 23 and a lower plug 24, the gas introduced into the high pressure chamber 21 through the pressure introduction hole 25 provided in the upper plug 23 passes through the upper sealing ring 26 and the lower sealing ring 2.
7 in a hermetically sealed manner within the high pressure chamber 21. The axial force acting on the upper plug 23 and the lower plug 24 causes both plugs 23 and 24 to move toward the high pressure cylinder 2.
It may be supported by screwing it to 2, or a mechanism may be adopted in which it is supported by a press. Heating device 28 installed on the lower plug 24
is constructed by holding the heating element 29 in electrical isolation within a metallic cylinder 30. or,
The heating element 29 is supplied with electrical power through an electrode 31 which is electrically insulated and hermetically arranged on the lower plug 24 . Processing chamber 3 including heating device 28
A heat insulating exterior 33 surrounding the heat insulating shell 33 is composed of substantially concentric inverted tips 34 and 35 made of a material with low gas permeability and a ring 36, and the inside is filled with a fibrous heat insulating material 37 such as ceramic fiber. Ru. An example of the use of the high-pressure, high-temperature furnace of the present invention having the above configuration will be shown below. First, the lower plug 24 is taken out of the high pressure chamber 21 together with the heat insulating sheath 33 and the heating device 28, and the heat insulating sheath 33 placed on the lower plug 24 is placed on the lower plug 2.
4 to open the inside of the processing chamber 32, take out the object to be processed 48 to be placed on the lower plug 24 via the heat insulating material 43, insert a new object to be processed, and then remove the heat insulating exterior 33 . It is placed on the lower plug 24 to shut off the processing chamber 32, and supplies power to the heating element 29 in the processing chamber 32 through the electrode 31 to raise the temperature in the processing chamber 32, thereby preheating the object to be processed 48. ,
When the object to be processed 48 has been preheated to a predetermined temperature, the lower plug 24, the object to be processed 48, and the heat insulating exterior 3
3. After inserting the heating device 28 integrally into the high pressure chamber 21 and sealing the inside of the high pressure chamber 21 with the lower sealing ring 27, the high pressure chamber 21 and the processing chamber are sealed through the pressure introduction hole 25 provided in the upper plug 23. 32 vacuum suction is performed, and then gas replacement is performed. After the gas replacement is completed, gas is continuously supplied from the pressure introduction hole 25 and power is continuously supplied to the heating device 28 to perform processing work on the object to be processed 48 under high pressure and high temperature. In addition, in equipment equipped with a separate heating device for preheating, the preheated object 48 is placed outside the high pressure chamber 21 in the processing chamber formed by the lower plug 24 and the heat insulating exterior 33 . 32 and inserted into the high-pressure chamber 21 as is, or the object to be processed 48 can be heat-retained and heated by supplying power to the heating device 28 and then inserted into the high-pressure chamber 21. When this is not necessary, the object to be processed 48 can be accommodated in the processing chamber 32 outside the high pressure chamber 21 and inserted into the high pressure chamber 21 as it is, and a desired method of use can be adopted. That is, according to the invention as described above, when performing preheating, the heating device 28 used for high pressure and high temperature treatment can be used as the heating device, so there is no need to separately provide a heating means such as a preheating furnace, and the equipment cost is reduced. In addition, since the object to be processed 48 is placed in the processing chamber 32 formed by the heat insulating exterior 33 and the lower plug 24 during and after preheating, heat loss due to heat radiation is significantly reduced. Moreover, even when the preheated high-temperature processing object 48 is inserted into the high-pressure chamber 21, the lower inner wall surface of the high-pressure cylinder 22 is not overheated because the processing object 48 is shielded by the heat-insulating exterior 33 . Also, the lower sealing ring 27
The high-pressure cylinder 22 and the lower sealing ring 27 will not be damaged, and the life of the high-pressure cylinder 22 and the lower sealing ring 27 will be significantly extended, and safety will be dramatically improved. In addition, the heat insulating exterior 33 is an inverted cup 34, 35.
Although we have shown an example of using an integrally constructed one, the same effect can also be obtained by using one that is divided into a cylindrical side heat insulating sheath and a plate-like upper insulating sheath. However, as in the example, an inverted cup 3
A heat insulating exterior 3 integrally constituted by 4 and 35
3, the insulated sheath 33 not only serves as an effective thermal shield against conductive and radiant heat transfer, but is also particularly effective against convective heat transfer, which is a major part of heat transfer at high temperatures and pressures. Demonstrates heat insulation function. Furthermore, when using a heat insulating sheath with a split configuration, the object to be processed can be taken in and out by lifting the side insulating sheath and the top insulating sheath from the lower plug, or by removing only the top insulating sheath. It's okay to get old. That is, according to the above invention, a high-pressure, high-temperature treatment process with an extremely short cycle time can be carried out safely and economically without adversely affecting each part of the apparatus.

[Brief explanation of the drawing]

FIG. 1 is a front sectional view showing a conventional high-pressure high-temperature furnace, and FIG. 2 is a front sectional view showing an embodiment of the present invention.
21 is a high pressure chamber, 22 is a high pressure cylinder, 23 is an upper plug, 24 is a lower plug, 25 is a pressure introduction hole,
26 is an upper sealing ring, 27 is a lower sealing ring,
28 heating device, 31 electrode, 32 processing chamber, 33
numeral 48 indicates a heat insulating exterior, and 48 indicates an object to be processed.

Claims (1)

[Claims] 1 A high-pressure cylinder, a high-pressure chamber formed by an upper plug and a lower plug that seal the upper and lower openings of the high-pressure cylinder, respectively, has an insulating exterior and a heating device inside the insulating exterior; In a high-pressure, high-temperature furnace in which a workpiece placed on a lower plug is subjected to a process such as sintering or bonding in a high-pressure, high-temperature gas atmosphere, the lower plug, heating device, heat-insulating exterior, and workpiece are placed outside the high-pressure cylinder. A high-pressure, high-temperature furnace characterized in that a processing chamber defined by the heat-insulating exterior and the lower plug is provided so as to be freely openable and closable.